Method of making molded rubber articles



Jan. 1, 1935. L, H. LHoLLlER 1,986,637

` METHOD 0F MAKING MOLDED RUBBER ARTICLES Filed June 2l, 1953 2Sheets-Sheet 2 J5 il E Patented" Janl, 1935 i invention relates to'procedurel for making articles, having molded rubber surfaces, :such for`example as' rubber shoes, the surfaces .oflwhich are i formed: in simitation of i leather, :fabric or other surface designs, "Ths inventionis` animprovement upon,` the subject matter of 'the co-` A '7,` 1932,`for Molded 'rubber article andY process .of

55 `suc'zh l thatI of anl alligator,

. making the same? and my copendingapplication, Serial No. 604,909,filed April 13141932, for Molded rubber article and'method ofrnakingthe-wsarne.`

LmlObjects of the invention" are to provide `for re" producing `thedesired design inzlarge numbers of rubber articles; and `to providea.Alargenumber Iof reproducing matrices and forms "even in the4base-:whererthematerial y of an easily destructibleriaturefandcan-@withal standfonly a comparatively. few 'direct' impressions, aswhere the original :surf ace is of leather and?" a1 coagulant having.leather-deteriorating properties 4is used inthe Vrubber'rrnoldingf:process. ji.. Related objects areftoprovide for convenience',

Vrapidity and and to maintain a high degreeiof f1delity;in"re-`producing `the details lofjdesign ,-of the original surface# i ifgTheiim/ention makes sensible-thesreneatedilse of.' then design of a ncomparatively! small original This constitutes "ajconsderableu'advantage over `procedures wherein 4the iinal'a'rticlesgi or` evenskins, and wherein considerable waste necessarily results from the`expedient*of*approximately matching the skins, especially as itoftenbhappensf that i an 1 otherwise i desirable skin isfpartlyblemished by the'presence.` of `wound marksior other malformation. These"disadvantages are 'largelyovercomelbyithe presentinvention; i fflI'ntheaccompanying `d rawi'ngsrgf` i lLFigs`. 1"to 6,\"inclusive, are`enlarged cross-2 sections ofelementsused in successive stages' of theprocedure 'a'c'c'ordingto the invention in'iits preferred form; `Fig. `1'illustrating afreptile` skin, whose'- surfac'e vdelf Hood RubberCompany,Inc.;-Watertown;Mass:,

f a corporation of Delaware f v Q :application .rune el; ieee; 'seriall[5i 'oiaimsj (01.* 184.61)

ofthe original surface i is A .economy in the'reproducing process thedesign-.'-`

Surfa over. e 1er-ger serien@ altfaef.` the naar tii engins;

two "skins being exactly alike."

` From thexelectrotypetheregi ,tive matrix `15,.` 'of'ganyl` suitablematerial, such as sign it is desired to reproduce; Fig. 2. a-softnegative matrixtlFig, 35a: positive electrotype associatedwith the softnegative matrix; Fig. 4- the detached `positive =electrotype Fig. 5 aihard negative'n'iatriwin associationfwith `the positive eleotrotypecandFig: 6 Aa positive crm-building sheet..- of "rubber .iinnegative-matrix.' i". r

lig."` L'I.-` is. a.. plan "view Vofl building sheet. 1 V i i-.Fig.f.8is an elevation-oda shoe support having partly builtwuponita'fpositive article-forming matrix; i 1: ,i A.wEigiQ is ant enlargedAcross-sec'ztion of'a'sheet of Athe `inni-nieul form# formebuildingrubber in` association with a nega# i tive. matrixehaving vanLundercutdesign illustrating a modification of..:the1procedure. n, ..iReferringtoztheadrawings.4 a negative matrix .12 isformed-upon an originalsurfacexserving as a positive: matrix,` .the originall surfaceillustrated beingthat ofanlalligator skin `lhaving irregw-` largrooves121,` .11 in its. surface; c: TheV negative matrixlz islpreferably`ofuunvulcanized rubber composition.:zwhichmisi soft,H and is preferablyformediby.:depositing'rthe:` rubber from agdispersion `of .theuatterupon the skin 10with the aid of@ a coagulant, although -preferably apreliminar-y. deposit formed ,upon lthe skin -without a coagulantordentmprovide a. rubber surface accurately conforming Yto the minute`details Vof After at least aV partial ,drying,` theunvulcanizedafrubberplZ b is suiciently `tenacious' toberremoved; :fromTthe skin' andiy handled without permanentzdistortion of its surface.'Preferably f without f lvulcanizing i 1 the? s soft( negative "matrix125er subjectingit to anyother treatment tliatgniight`malformgits'isurface, it is' utilized to make a; positive electrotypei13 ,f i any; suitable process for producing electrotypesi Before thesheet-l deposited` metal-i5 removed fromthe `softi1 'iat x12thegelectro-gdeposited:metal may be providedwit .a reinforcing iback14,`also of ,g The `positive electrotypetis then removedfrom the ,soft-matrixand -israsiwshown in Fig. 4, providing a permanent and ruggedreproduction` of thaOriginalisurracedesign.. n i 1 s formed alnegaa-phenolic condensate composition or vulcanized rubber, which'isxdesirablyhad and reinforced, as withfabriclplies 15"1; for the sakeof rugged# ness,` i and is highly? resistant i to the corrosive actionof coagulants-which may. be Vused subsequently :in moldingfrubberlagainst its. This negassociation with Jthe i hard ciation witlislone:another simply triX preferably by depositid'iffthubff from a liquidLdispersion of the same with the aid of a coagulant. The being highlyresistant to ii/'ear to' the ytctior'i of such ingredients as acidscdlnmnly used in coagulants, a large number of rubber sheets may beformed from the nttrix bythe dieperev I sion deposition process infaithful reproduction of the surface of the original skin. :The sheet?rubber-"16 removed fron'i the matrix land-'maybe built-directly into nalarticles if desired; butlinrorder to produce large numbers of. thearticles in. virtually exact reproe duction arid to lfacilitate `suchprocedure and avoidwastei, it :is-preferred toginake one 4or moremaster',forziisgfromthe sheet-rubber 16 and to produce the finalarticles in reproductionv of the shape andsurface design fofthefmasterxform.

For this purpose, `the sheet 1621s- Vi dried, if itis madebydeposition-from apliquid dispersion of the rubber; sarily, bevulcanized. A fabric backing 18 may be [adhered to `the sheet toreinforce it,A this fabric preferablyv being-of 'such weaveas to .peremit 'Sonie stretching of ,theisheet in' subsequently distorting ittoiormsh..l.1|`e..v .@1' i ,-Itis then cut; insuitablel shapes, such as theshoe; parts;16a,. 1617,` 'and 16e-shown in Fig. 7, and theselpartsxarethen assembled uponY a sup-` port 17 Figr8).so as to-'prsentzanouter sur facecorrespondingv to: that desired. in the nal articles..

andfalso strettlfiable= it may be curvedfto :the

.- As. the rsheet `i'nate-ial` is distortable shape' of theYforniismoothly and without wrm'- kles. The part's may .be sewnftoget erby s'titcliL ing -19, preei'sely',as'.iparts of i yleather *slices i.are sewn together;A or th'e.parts'lmay .belieldlin assos' by -ineanssofan adliesivezoiholdigthem onto'the supporter onto 4`each othe'r'.Ina'srnucli as the sheet-113 can be. duplicated finally' t-nfes, the:builderof: `-tlie master r formaten if `desirec'i utilize la;-oliice1por tionjoftheidsign on several-'.parts-'ortlie saineformirzandf initneeaseffof suenartielesfas shoes, onj the Ytwoinsiste-r-Yfornis` forY the .1`pair, instead of having to'resort-tortheiiexpedient of approxis mate matching;I wliicniliefwould hve to do if the Aforms'were to be builtfup "from original skins.

Alsman error inciittiiig 'the f case of a raredesigngpwoiild no wouldwere vthe original being etsisgllin 'the bev fatal as it clit.

The built-up master form'isvuseqtoproduce" "Ihelatter, when-.removed andturned inside out,

constitutes a male-'negativaJand lupon lthis is 'deposited a .Affemale-psitivep which, when removed `and turnedinside tout, .Lp'resentsthe male positive outer surface 'ofitheflnal article. In .th'ecasepfzfoptweair, .such (parts las failin- 6) with a positive surfacefdesign. The rubber is molded against the nia" composition ofthe matrix15,

and it may; though V'not necesa Y parts ,of a single ior,l

1,9865637 i M i' ing, reinforcement, and sole and heel parts may beapplied during the process, and the article vulcanized in open heat upona support as disclosed in said copending application.

Owing to the great multiplicity of forms that can be convenientlyproduced with surface designs in virtually exact reproduction of theorigin'al vention is well suited to large scale production, and as thecost of the material having the origial design is divided among a largenumber of final. articles, rare 'and costly skins and other designedmaterials can be used with comparatively low cost for the design in thenal article. A Occasionally Oit isjdesired vto reproduce the de- -signof a reptile skin or other surface having deeply undercut recesses inthe surface such as" to` render it difficult, if not impossible, towithdraw a non-resilient material molded against it without injuring oneor the other of the surfaces. -It has been found that good results'insuch .cases may be obtained by forming v'from the original surface asoft rubber' negative inatrix, as in the step of the above describedprocedure corresponding to Figuz, and thenfinstead of forming anelectrotype from such softnega` tive matrix, usingit directly to form" apositive forni-building sheet, as illustrated in Fig. 9, the softnegative matrixbeing indicated at 21, and thesheet rubber'which isformedagainst it being designated 22.- The rubber.sliieet-22V may beformed upon'the matrix -21-by depositing .the rubber from a dispersionwith the aid 'of a coagulant as described for theformiiig of sheets16,and may likewise be fabric backed before being removed from thematrix for cutting 4and assembly into the master form. As :both thematrix 21 and the sheet 22 are of resilient rubber, separation of thetwo undercuts in the design.I 'f f Y If desired, the matrix 21 may be ofhard rub berV composition which is removed from the nia tri'x in a softstate and isi then vulcanized. With this, theA yieldability-and'resilience Yof the rubber layer;.22 is relied :upon for safe reriiovalvof it fronrthe` matrix Without damage resulting from'undecut recesses inthe desig'r'i. F Wliile by'this-procedurethe number of sheets 22possible to make is notas great as in r.the if)ceiiilfehreinbefore."described where the original desig'nis Infiade vmorenearly` permanent electrotype'aiidthe haidmatrices, yet the niin'iberiofreproductions .()s'sibleI is' considerably 'v'vl'iere'- the'form isbuilt greater than' in the cas ,A l directly front the originalniateriai,1 and this procedure "has the dviitafgesffalso of convenlfence, speed and economy, "and of giving the builder of the master-form;considerablefreedom in using choicevportions of a design onseveral pairof master forms with-K out-having to resortv to the fexpedient of ap'-proxiniate matching of skins. a

I claim:

1. The method of article which `comprises molding a layer of rubberagainst an element' ofr which the surface configurationV is to bereproduced inrubber to produce a negative rubber matrix,A producing bymeans of said matrix ajsheet of4 rubber having moldedin its Vsurface a-reproductiongof said cone figuration, shaping. in contoured =-form,upon a form-support a pluralityf'of pieces vofrubber ini cluding .atVleast llione piege j'of-A the molded rubber surfaces,A the procedure,ofthe present inwithout injury tolthe surfaces, is facilitated, evenwith pronounced producing 'a molded rubber f A article having as a sheetto provide ajmatriir lform, and molding a the rubber of said matrix is`yet soft and `unlvulcanized producing an electrotype of its face, and bymeans of said` electrotype producing a layer of plastic material `havingmoldedvin its" `face a reproduction of said conguration.

3. The method of making a contouredrubber surface design areproductionof the `,surface of plastic material byvmolding a reproduction of thesurface designof the article, shaping a plurality of pieces of design.

rubber, to

designiof a chosen articlel which comprises producing in a flexiblesheet 4. The method of making a contoured rubber article having as asurface design a reproduction of the surface design of a chosen articlewhich comprises producing in rubber in sheet form by molding areproduction of the surface design of the article, shaping a pluralityof pieces of rubber including at least one piece of said molded rubberin contoured form upon an internal form-support to provide a form iform-matrix producing rubber the final conmatrix and from said bymolding in a layer of toured article having in its surface a reproduc-`tion of the'design;` i n f5. The method of making negative matrix formsfor `molding contoured rubber articles with a surface design reproducedfrom a chosen article which comprises producing in a flexible sheet ofplastic material a positive reproduction of the surface design of thearticle, shaping said material in contoured form upon a formsupporttoprovide a pos'tive, contoured matrix form, and molding a plurality ofcontoured negative forms from the said positive form.`

LESLIE H. LHOILIER.

